Development of the Technology for Processing Plant Breeding By-Products to Obtain Biosorbent

This study focuses on the potential transforming sunflower husk wastes into innovative green products to be used for the recultivation of contaminated soils. This transformation makes it possible to utilize the large quantity plant breeding by-products to obtain a highly porous biosorbent. Optimal conditions for the preparation of bisorbents can be determined based on measurements of their specific surface and porosity. It is shown that structural characteristics of sorbent depend on conditions of the pyrolysis of primary raw material. Optimal conditions for obtaining biosorbent with a specified proportion of mesoand micropores and high specific surface are performed under three-stage pyrolysis as given by following conditions: sample holding time of 10-30 min, final temperature 700°С, and heating rate 15°С/min. A 3-month incubation study was conducted to investigate its performance in stabilization of copper contamination in Fluvisol. The sequential extraction procedure showed that the 1% sunflower husks biosorbent treatment reduced the mobile pool (exchange and carbon-bonded fractions) of Cu from 8 to 4%, respectively, compared to the contaminated soil. Cu is found to be tightly bonded owing to the increase of the residual and organic matter-bonded metal fractions. Owing to its adsorptive properties, biosorbent amendment of coppercontaminated soils appears as a promising approach to reduce the pollutant mobility and bioavailability

Formation of Biochar Nanocomposite Materials Based on CoFe₂O₄ for Purification of Aqueous Solutions from Chromium Compounds (VI)

The paper proposes a simple one-stage synthesis of organic-inorganic composite materials based on oxide compounds of iron (III) and cobalt (II) with a developed surface. The process of cobalt(II) ferrite (CoFe2O4) structure formation on the biochar surface was studied. As an organic component, biochar was obtained from agricultural waste, including sunflower husks, rice husks, and pea kernels. Composite materials cobalt ferrite/biochar were obtained for the first time using these wastes. The obtained materials were characterized using X-ray phase analysis, fourier transform infrared spectroscopy (FTIR), transmission electron microscopy, and N2 adsorption-desorption. A mechanism for forming composite materials is proposed, including the stage of formation of chelate complexes of transition element cations with citric acid on the biochar surface and their subsequent thermal decomposition. High adsorption activity of the synthesized materials in the process of removing chromium (VI) ions from aqueous solutions was established. The sunflower husk biochar composite material based on CoFe2O4 has the highest adsorption capacity of 6.98 mg/g. The results suggest that biochar composites based on CoFe2O4 have great potential for the practical industrial wastewater treatment